This invention relates to forwarding network packets between network domains.
Packets are routed through a series of router devices, each of which stores and forwards packets on its way from a source to a destination. For example, a packet may start out as an Internet packet, be forwarded over an ATM (asynchronous transfer mode path) and then back to Ethernet onto a corporate network to its final intended recipient. As the network passes through these network domains, various header encapsulations may be added to or removed from the packet. Some connections use point-to-point protocol (PPP) whereas others use multiprotocol label switching MPLS, layer to tunneling protocol LTTP, ATM and so forth.